Burner Assembly and Heat Exchanger

ABSTRACT

Systems and methods are disclosed that include providing a cooking system that comprises a burner assembly and a heat exchanger submerged in a vessel. The burner assembly includes a high velocity burner and a low velocity burner, the high velocity burner configured to provide the necessary high velocity, volumetric flowrate through a fluid duct of the heat exchanger that includes a plurality of compactly-arranged, alternatingly-disposed vertical and horizontal tubes passing through the fluid duct, and the low velocity burner configured to significantly reduce and/or substantially eliminate “lift off” that could result from operation of only the high velocity burner. The heat exchanger is submerged in the vessel with the tubes of the heat exchanger open to the vessel to allow ingress and egress of a fluid contained within the vessel.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application No. 62/271,838 filed on Dec. 28, 2015 by Souhel Khanania, and entitled “Burner Assembly and Heat Exchanger,” the disclosure of which is hereby incorporated by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND

Food service equipment often includes heat generation equipment and/or heat transfer equipment to produce and/or transfer heat to a cooking medium contained in a cooking vessel for cooking consumables prior to packaging. Such heat generation equipment and/or heat transfer equipment often includes a burner configured to combust an air/fuel mixture to produce heat and a heat exchanger to transfer the heat produced by the burner to the cooking medium. Traditional food service burners and/or heat exchangers may often be inefficient at transferring heat to the cooking medium and/or require frequent monitoring and/or replacement of the cooking medium.

SUMMARY

In some embodiments of the disclosure, a cooking system is disclosed as comprising: a burner assembly; and a heat exchanger, comprising: a plurality of walls that form a fluid duct configured to receive a combusted air/fuel mixture from the burner assembly; and a plurality of tubes disposed across the fluid duct and configured to receive fluid therethrough; wherein the heat exchanger is connected to the burner assembly and disposed within a vessel.

In other embodiments of the disclosure, a method of operating a cooking system is disclosed as comprising: providing a burner assembly configured to combust an air/fuel mixture; providing a heat exchanger comprising a plurality of walls that form a fluid duct configured to receive a combusted air/fuel mixture from the burner assembly, and a plurality of tubes disposed across the fluid duct and configured to receive fluid therethrough; disposing the heat exchanger in a vessel that contains a fluid; allowing fluid to at least partially fill the plurality of tubes; combusting the air/fuel mixture in the burner assembly; and transferring heat resulting from the combustion of the air/fuel mixture to the fluid within the plurality of tubes.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description:

FIG. 1 is an oblique side view showing a partial cross-section of a burner assembly according to an embodiment of the disclosure;

FIG. 2 is an oblique front view showing the partial cross-section of the burner assembly of FIG. 1 according to an embodiment of the disclosure;

FIG. 3 is a detailed oblique front view of the partial cross-section of the burner assembly of FIGS. 1-2 according to an embodiment of the disclosure;

FIG. 4 is an oblique bottom view showing the partial cross-section of the burner assembly of FIGS. 1-3 according to an embodiment of the disclosure;

FIG. 5 is an oblique cross-sectional right side view showing the partial cross-section of the burner assembly of FIGS. 1-4 according to an embodiment of the disclosure;

FIG. 6 is an oblique side view of a heat exchanger according to an embodiment of the disclosure;

FIG. 7 is an oblique cross-sectional side view of the heat exchanger of FIG. 6 according to an embodiment of the disclosure;

FIG. 8 is schematic top view of a cooking system according to an embodiment of the disclosure;

FIG. 9 is a schematic side view of the cooking system of FIG. 8 according to an embodiment of the disclosure; and

FIG. 10 is a schematic top view of a cooking system according to another embodiment of the disclosure.

DETAILED DESCRIPTION

In some cases, it may be desirable to provide a cooking system with a burner assembly having a high velocity burner to force combusted air and fuel through a heat exchanger and a low velocity burner to maintain a continuous combustion process and prevent so-called “lift off” where a flame and/or combustion process may be extinguished by a high velocity combustion process that exceeds the ignition capabilities of the burner assembly. For example, where a heat exchanger is submerged in a cooking vessel and comprises a plurality of compactly-arranged, interstitially-spaced vertical and horizontal tubes that are open to the cooking vessel to allow ingress and egress of a cooking fluid, resistance to fluid flow through a fluid duct of the heat exchanger may be excessive, such that traditional burners would fail to pass combusted air and fuel through the heat exchanger and would suffer from “lift off” if the velocity and/or flowrate of combustion was increased. Accordingly, a cooking system is disclosed herein that comprises providing a burner assembly having a high velocity burner configured to provide the necessary high velocity flowrate through a heat exchanger having a plurality of compactly-arranged, interstitially-spaced vertical and horizontal tubes that are open to the cooking vessel to allow ingress and egress of a cooking fluid, and a low velocity burner configured to significantly reduce and/or substantially eliminate “lift off” that could result from operation of only the high velocity burner.

Referring now to FIGS. 1-5, various views of a burner assembly 100 are shown according to an embodiment of the disclosure. The burner assembly 100 generally comprises a body 102, a manifold 110, a plurality of runners 112 joining the body 102 to the manifold 110, a plurality of first burners 126, a plurality of second burners 138, a ribbon burner 146, and a plurality of deflectors 122. The body 102 comprises a lower portion 104 joined to an upper portion 106. In some embodiments, the lower portion 104 may be bolted to the upper portion 106 using fasteners 124 disposed through holes in the lower portion 104 and threaded into the upper portion 106. In some embodiments, a gasket 108 may be disposed between the lower portion 104 and the upper portion 106 of the body 102 to prevent leakage and/or seepage of any fluid flowing within the cavity 105 from escaping between the lower portion 104 and the upper portion 106. When assembled, the lower portion 104 and the upper portion 106 generally form a cavity 105 through which fuel and/or an air/fuel mixture may flow.

The burner assembly 100 also comprises a manifold 110 configured to deliver the fuel and/or the air/fuel mixture into the cavity 105 through a plurality of parallel runners 112. Each runner 112 comprises a lower threaded portion 114, an upper threaded portion 116, and a butt joint 118 that joins the lower threaded portion 114 to the upper threaded portion 116. In some embodiments, it will be appreciated that each runner 112 may be a solid piece and comprise the lower threaded portion 114 and the upper threaded portion 116 joined by the butt joint 118. The lower threaded portion 114 may generally be threaded into and extend into an inner opening of the manifold 110, such that fuel and/or an air/fuel mixture may flow from an internal volume of the manifold 110 through an internal volume of the lower threaded portion 114 and into an internal volume of the butt joint 118. The upper threaded portion 116 may generally be threaded into the lower portion 104 of the body 102 and extend into the cavity 105 of the body 102. Accordingly, an internal volume of the upper threaded portion 116 may receive fuel and/or an air/fuel mixture from the internal volume of the butt joint 118. It will be appreciated that each runner 112 thus comprises a fluid flow path that extends through internal volumes of the lower threaded portion 114, the butt joint 118, and the upper threaded portion 116. Furthermore, the upper threaded portion 116 comprises a plurality of fuel delivery holes 120 that may distribute the fuel and/or the air/fuel mixture received from the manifold 110 evenly throughout the cavity 105. Additionally, in some embodiments, an upper distal end of the upper threaded portion 116 may be closed and/or substantially abut a substantially flat surface of the upper portion 106 of the body 102 so that the fuel and/or the air/fuel mixture that passes through the runner 112 only escapes the upper threaded portion 116 through the fuel delivery holes 120.

The burner assembly 100 comprises a plurality of first burners 126 arranged adjacently along a length of the upper portion 106 of burner assembly 100. Additionally, the plurality of first burners 126 are arranged along a centerline of the upper portion 106 of the body 102, such that the centerline of the body 102 intersects a center axis of each first burner 126. Each first burner 126 comprises a cylindrically-shaped first bore 128 configured to receive the fuel and/or the air/fuel mixture from the cavity 105. The first bore 128 also comprises a plurality of holes 132 disposed about the first bore 128 that are configured to allow the fuel and/or the air/fuel mixture to flow from the first bore 128 to a combustion chamber 134 that is formed by a cylindrically-shaped third bore 130. Each first burner 126 also comprises a cylindrically-shaped second bore 129 that is axially aligned with and disposed downstream from the first bore 128 with respect to the flow of the fuel and/or the air/fuel mixture through the burner assembly 100 and that comprises a diameter that is smaller than the diameter of the first bore 128. The second bore 129 may also receive the fuel and/or the air/fuel mixture from the first bore 128. In some embodiments, the smaller diameter of the second bore 129 may be sized to control a pressure drop through the second bore 129 and/or the plurality of holes 132 disposed about the first bore 128.

Accordingly, the first burner 126 may define a first flowpath 131 from the cavity 105 through the first bore 128 and the second bore 129 into the combustion chamber 134 and further define a plurality of second flowpaths 133 from the cavity 105 through the first bore 128, through the plurality of holes 132, and into the combustion chamber 134. Furthermore, as will be discussed herein in further detail, to ignite the fuel and/or the air/fuel mixture in the first burner 126, each first burner 126 also comprises a groove 136 disposed in the third bore 130 that forms the cylindrically-shaped combustion chamber 134 on each of an opposing left side and right side of the combustion chamber 134 so that fuel through the first flowpath 131 and the plurality of second flowpaths 133 of the first burner 126 may be ignited by the ribbon burner 146. In some embodiments, the flowrate and/or volume of the fuel and/or the air/fuel mixture through the first flowpath 131 of the first burner 126 may be greater than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second flowpaths 133 through the first burner 126. However, in other embodiments, the flowrate and/or volume of the fuel and/or the air/fuel mixture through the first flowpath 131 of the first burner 126 may be equal to or less than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second flowpaths 133 through the first burner 126.

The burner assembly 100 also comprises a plurality of second burners 138 disposed on each of a left side and a right side of the upper portion 106 of the body 102 of burner assembly 100. Each second burner 138 may generally be configured as a low flow-rate ribbon burner 146 that comprises a plurality of feeder holes 140, a cavity 142, and a plurality of upper holes 144. The feeder holes 140 are configured to receive the fuel and/or the air/fuel mixture from the cavity 105 and allow the fuel and/or the air/fuel mixture to flow into a cavity 142 that houses the ribbon burner 146. The second burner 138 also comprises a plurality of upper holes 144 that are disposed on the left and right sides of the cavity 142 and the ribbon burner 146. The upper holes 144 receive fuel and/or air/fuel mixture from the cavity 142. Accordingly, the second burner 138 may define a first flowpath 141 from the cavity 105 through a plurality of feeder holes 140, into the cavity 142, and through a plurality of upper holes 144. Furthermore, as will be discussed herein in further detail, the fuel and/or the air/fuel mixture flowing through the upper holes 144 may be ignited by the ribbon burner 146.

Additionally, the ribbon burner 146 comprises a plurality of small perforations 148 that may also allow the fuel and/or the air/fuel mixture to pass through a plurality of second flowpaths 143 from the cavity 142 through the perforations 148, where they may be ignited by the ribbon burner 146. In some embodiments, the flowrate and/or volume of the fuel and/or the air/fuel mixture through the first flowpath 141 of the second burner 138 may be greater than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second flowpaths 143 through the second burner 138. However, in other embodiments, the flowrate and/or volume of the fuel and/or the air/fuel mixture through the first flowpath 141 of the second burner 138 may be equal to or less than the flowrate and/or volume of the fuel and/or air/fuel mixture through the plurality of second flowpaths 143 through the second burner 138. Additionally, in some embodiments, the combined flowrate and/or volume of the fuel and/or the air/fuel mixture through a first burner 126 may be greater than the flowrate and/or volume of the fuel and/or the air/fuel mixture through a second burner 138. However, in alternative embodiments, the combined flowrate and/or volume of the fuel and/or the air/fuel mixture through a first burner 126 may be equal to or less than the flowrate and/or volume of the fuel and/or the air/fuel mixture through a second burner 138.

In some embodiments, the burner assembly 100 may comprise one or more infrared burners. Accordingly, the first burner 126, the second burner 138, and/or the ribbon burner 146 may be configured as an infrared burner. Accordingly, first burner 126, the second burner 138, and/or the ribbon burner 146 may comprise additional components, including but not limited to, ceramic components and/or other components necessary to configure and/or operate the first burner 126, the second burner 138, and/or the ribbon burner 146 as an infrared burner. However, in some embodiments, the first burner 126, the second burner 138, and/or the ribbon burner 146 may alternatively be configured as any other suitable burner.

In operation, the burner assembly 100 is configured to combust fuel and/or an air/fuel mixture through a plurality of first burners 126 and a plurality of second burners 138. In some embodiments, the burner assembly 100 may also comprise a separate igniter and/or a plurality of igniters configured to ignite the air/fuel mixture in each of the first burners 126 and second burners 138. In this embodiment, the combined flowrate and/or volume of the fuel and/or the air/fuel mixture through the first burners 126 is greater than the flowrate and/or volume of the fuel and/or the air/fuel mixture through the plurality of second burners 138. Accordingly, the velocity of the combusted fuel and/or the combusted air/fuel mixture through the first burners 126 is higher than the velocity of the combusted fuel and/or the combusted air/fuel mixture through the second burners 138.

Because the velocity of the combusted fuel and/or the combusted air/fuel mixture through the first burners 126 exits the first burners 126 at such a high velocity, traditional burners may experience so-called “lift off” where the flame is extinguished due to the high velocity. As such, the lower velocity of the combusted fuel and/or the combusted air/fuel mixture exiting the second burners 138 may prevent this “lift off” by continuously burning fuel at a lower flowrate and/or delivering a combusted air/fuel mixture at the lower velocity. Additionally, the burner assembly 100 also comprises a deflector 122 on each of a left side and a right side of the upper portion 106 of the body 102 of burner assembly 100 that is secured to the upper portion 106 of the body 102 by a plurality of fasteners 124. The deflectors 122 may be angled towards a center of the upper portion 106 and extend over the second burners 138 in order to deflect the combusted air/fuel mixture exiting the second burners 138 towards the combusted air/fuel mixture exiting the first burners 126. Accordingly, the deflectors 122 may also aid in preventing “lift off” by directing the lower velocity combusted air/fuel mixture exiting the second burners 138 towards the higher velocity combusted air/fuel mixture exiting the first burners 126.

Referring now to FIGS. 6 and 7, an oblique side view and an oblique cross-sectional side view of a heat exchanger 200 are shown, respectively, according to an embodiment of the disclosure. The heat exchanger 200 generally comprises a top wall 204, a bottom wall 206, a left side wall 208, and a right side wall 210 that define a fluid duct 222 having an inlet 202 and an outlet 212 through the heat exchanger 200. Heat exchanger 200 also comprises a plurality of vertical tubes 214 that extend between the top wall 204 and the bottom wall 206. The plurality of vertical tubes 214 may extend through the top wall 204 and the bottom wall 206 to allow ingress and egress of fluid into the vertical tubes 214 through each of the top wall 204 and bottom wall 206. Additionally, heat exchanger 200 also comprises a plurality of horizontal tubes 216 that extend between the left side wall 208 and the right side wall 210. The plurality of horizontal tubes 216 may extend through the left side wall 208 and the right side wall 210 to allow ingress and egress of fluid into the horizontal tubes 216 through each of the left side wall 208 and the right side wall 210.

The vertical tubes 214 and the horizontal tubes 216 of the heat exchanger 200 may generally be arranged to provide a compact, highly resistive flowpath through the fluid duct 222. In order to effectively and/or evenly distribute the heat produced by burner assembly 100 through the vertical tubes 214 and the horizontal tubes 216, sets and/or rows of vertical tubes 214 may be interstitially and/or alternatively spaced with sets and/or rows of horizontal tubes 216. In the shown embodiment, two rows of vertical tubes 214 are interstitially and/or alternatively spaced with two rows of horizontal tubes 216 along the length of the heat exchanger 200. However, in alternative embodiments, a single row of vertical tubes 214 may be interstitially and/or alternatively spaced with a single row of horizontal tubes 216 along the length of the heat exchanger 200. In other embodiments, however, heat exchanger 200 may comprise any number of rows of vertical tubes 214 interstitially and/or alternatively spaced with any number of rows of horizontal tubes 216 along the length of the heat exchanger 200. For example, heat exchanger 200 may comprise three rows of vertical tubes 214 interstitially and/or alternatively spaced with two rows of horizontal tubes 216. Accordingly, it will be appreciated that the number of rows or vertical tubes 214 interstitially and/or alternatively spaced with rows of horizontal tubes 216 may vary, so long as at least one row of vertical tubes 214 is interstitially and/or alternatively spaced with at least one row of horizontal tubes 216 along the length of the heat exchanger 200.

The heat exchanger 200 also comprises a plurality of mounting holes 218 disposed through a mounting flange 220 that is disposed at the distal end of the heat exchanger 200 located closest to the inlet 202. The mounting holes 218 may generally be configured to mount the heat exchanger 200 to the burner assembly 100 of FIGS. 1-5. In some embodiments, the heat exchanger 200 may be secured to the burner assembly 100 via fasteners 124. However, in other embodiments, the heat exchanger 200 may be secured to the burner assembly 100 through an alternative mechanical interface. The heat exchanger 200 is secured to the burner assembly 100 so that combusted fuel and/or combusted air/fuel mixture is forced through the fluid duct 222 of the heat exchanger 200. Accordingly, heat from the combusted fuel and/or combusted air/fuel mixture may be absorbed by a fluid flowing through the tubes 214, 216 of the heat exchanger 200. The heated fluid may exit the heat exchanger 200 through the outlet 212 and therefore be used to heat and/or cook consumable products (i.e. chips, crackers, frozen foods).

In operation, the configuration of tubes 214, 216 provides a compact, highly resistive flowpath through the fluid duct 222. Accordingly, to force combusted fuel and/or combusted air/fuel mixture through the fluid duct 222 requires high velocity. Accordingly, the velocity of the combusted fuel and/or the combusted air/fuel mixture through the first burners 126 of the burner assembly 100 is high enough to provide the requisite velocity needed to overcome the resistance to flow through the heat exchanger 200. Furthermore, the lower velocity of the combusted fuel and/or the combusted air/fuel mixture through the second burners 138 of the burner assembly 100 prevents “lift off” so that the combustion process remains constant through the burner assembly 100.

Referring now to FIGS. 8 and 9, a schematic top view and a schematic side view of a cooking system 300 are shown, respectively, according to an embodiment of the disclosure. Cooking system 300 generally comprises at least one burner assembly 100, at least one heat exchanger 200, and at least one cooking vessel 302 (e.g. a fryer). As previously disclosed, the burner assembly 100 may be mounted to at least one heat exchanger 200. However, in this embodiment, the burner assembly 100 may be mounted to a plurality of heat exchangers 200. Furthermore, while not shown, in some embodiments, multiple burner assemblies 100 may be mounted to multiple heat exchangers 200 in the cooking system 300. The burner assembly 100 is configured to provide a high velocity flow of combusted fuel and/or combusted air/fuel mixture through the fluid duct 222 of the heat exchanger 200. The heat exchangers 200 may generally be submerged in the cooking vessel 302.

Fluid, such as a cooking fluid (e.g. oil) contained within the cooking vessel 302, may be free to flow through the vertical tubes 214 and horizontal tubes 216 of the heat exchanger 200. Heat produced from the combustion of fuel and/or an air/fuel mixture in the burner assembly 100 may enter the inlet 202 of the heat exchanger 200 from the burner assembly 100 and be transferred to the fluid flowing through and/or contained within the tubes 214, 216 of the heat exchanger 200. Accordingly, in embodiments comprising multiple heat exchangers 200, the heat exchangers 200 may be disposed throughout the cooking vessel 302 at substantially similar intervals and/or uniformly spaced to maintain a substantially uniform temperature within the cooking vessel 302. However, in other embodiments comprising multiple heat exchangers 200, the heat exchangers 200 may be disposed to maintain a temperature gradient and/or temperature profile within the cooking vessel 302. The heated fluid may exit the heat exchanger 200 through the outlet 212. In some embodiments, the outlet 212 may extend through the cooking vessel 302 and be discharged to an outside environment through a collective exhaust header (not shown) and/or any other ductwork to expel the combusted gases. In some embodiments, fluid from the cooking vessel 302 may be circulated within the cooking vessel 302 by a pump (not shown) to increase and/or promote fluid flow through the tubes 214, 216 of the heat exchanger 200. Furthermore, it will be appreciated while burner assembly 100 is disclosed in the context of food service equipment (e.g. cooking vessel, fryer, boiler), the burner assembly 100 may be used for any application or industry that requires a fluid to be heated rapidly, consistently, and efficiently.

Referring now to FIG. 10, a schematic top view of a cooking system 400 is shown according to another embodiment of the disclosure. Cooking system 400 may be substantially similar to cooking system 300 of FIGS. 8 and 9. However, in this embodiment, cooking system 400 comprises a plurality of burners, wherein each burner assembly 100 may be mounted to a single heat exchanger 200. The burner assembly 100 is configured to provide a high velocity flow of combusted fuel and/or combusted air/fuel mixture through the fluid duct 222 of the heat exchanger 200. The heat exchangers 200 may generally be submerged in the cooking vessel 302. Fluid, such as a cooking fluid (e.g. oil) contained within the cooking vessel 302, may be free to flow through the vertical tubes 214 and horizontal tubes 216 of the heat exchanger 200. Heat produced from the combustion of fuel and/or an air/fuel mixture in the burner assembly 100 may enter the inlet 202 of each heat exchanger 200 from the burner assembly 100 and be transferred to the fluid flowing through and/or contained within the tubes 214, 216 of the heat exchanger 200. Additionally, heat may be transferred to the fluid within the cooking vessel 302 that contacts any outer surface of the heat exchangers 200.

In this embodiment, the heat exchangers 200 may generally be disposed throughout the cooking vessel 302 at substantially similar intervals and/or uniformly spaced to maintain a substantially uniform temperature within the cooking vessel 302. However, in other embodiments, the heat exchangers 200 may be disposed at any other interval and/or spacing based on a desired temperature profile across the cooking vessel 302 and/or the configuration of the cooking vessel 302. Thus, in some embodiments, the burner assemblies 100 and heat exchangers 200 are disposed to maintain a temperature gradient and/or temperature profile within the cooking vessel 302. In addition, to accomplish control of the burner assemblies 100, each burner assembly 100 may be controlled by a burner assembly controller 402. As such, the burner assembly controller 402 may control each burner assembly 100 to a specified amount of heat in order to maintain a temperature gradient and/or temperature profile of the fluid within the cooking vessel 302. However, in other embodiments, the burner assemblies 100 may be controlled to provide a substantially similar amount of heat to maintain a substantially similar temperature of the fluid throughout the cooking vessel 302. In such embodiments, multiple burner assemblies 100 may, at least in some instances, be controlled by a single burner assembly controller 402. The heated fluid may exit the heat exchanger 200 through an outlet 212 in each heat exchanger 200. In some embodiments, the outlet 212 may extend through the cooking vessel 302 and be discharged to an outside environment through a collective exhaust header (not shown) and/or any other ductwork to expel the combusted gases. In some embodiments, fluid from the cooking vessel 302 may be circulated within the cooking vessel 302 by a pump (not shown) to increase and/or promote fluid flow through the tubes 214, 216 of the heat exchanger 200. Furthermore, it will be appreciated while burner assembly 100 is disclosed in the context of food service equipment (i.e. cooking vessel, fryer, boiler), the burner assembly 100 may be used for any application or industry that requires a fluid to be heated rapidly, consistently, and efficiently.

At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, R₁, and an upper limit, R_(u), is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R₁+k*(R_(u)−R₁), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Unless otherwise stated, the term “about” shall mean plus or minus 10 percent of the subsequent value. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. 

What is claimed is:
 1. A cooking system, comprising: a burner assembly; and a heat exchanger, comprising: a plurality of walls that form a fluid duct configured to receive a combusted air/fuel mixture from the burner; and a plurality of tubes disposed across the fluid duct and configured to receive fluid therethrough; wherein the heat exchanger is connected to the burner assembly and disposed within a vessel.
 2. The cooking system of claim 1, wherein the burner assembly comprises a first burner configured to combust an air/fuel mixture at a first flowrate and a second burner configured to combust an air/fuel mixture at a second flowrate.
 3. The cooking system of claim 2, further comprising: an igniter configured to ignite the air/fuel mixture in each of the first burner and the second burner.
 4. The cooking system of claim 1, wherein the heat exchanger comprises a plurality of vertical tubes that extends between a top wall and a bottom wall of the fluid duct.
 5. The cooking system of claim 4, wherein the plurality of vertical tubes are open to the vessel to allow ingress and egress of a fluid within the vessel.
 6. The cooking system of claim 1, wherein the heat exchanger comprises a plurality of horizontal tubes that extends between a left side wall and a right side wall of the fluid duct.
 7. The cooking system of claim 6, wherein the plurality of horizontal tubes are open to the vessel to allow ingress and egress of a fluid within the vessel.
 8. The cooking system of claim 1, wherein the heat exchanger comprises a plurality of vertical tubes that extend between a top wall and a bottom wall of the fluid duct, and wherein the heat exchanger comprises a plurality of horizontal tubes that extend between a left side wall and a right side wall of the fluid duct.
 9. The cooking system of claim 8, wherein the wherein the plurality of vertical tubes and the plurality of horizontal tubes are open to the vessel to allow ingress and egress of a fluid within the vessel.
 10. The cooking system of claim 9, wherein the plurality of vertical tubes are arranged in a plurality of sets of rows between the left side wall and the right side wall, and wherein the plurality of horizontal tubes are arranged in a plurality of sets of rows between the top wall and the bottom wall.
 11. The cooking system of claim 10, wherein the sets of rows of vertical tubes are alternately spaced with sets of rows of the plurality of horizontal tubes.
 12. The cooking system of claim 11, wherein the heat exchanger is configured to transfer heat produced from combusting an air/fuel mixture in the burner assembly to a fluid within the plurality of vertical tubes and the plurality of horizontal tubes of the heat exchanger.
 13. The cooking system of claim 12, wherein the burner assembly comprises a plurality of heat exchangers connected to the burner assembly.
 14. The cooking system of claim 12, wherein the vessel is configured to cook a consumable food product.
 15. A method of operating a cooking system, comprising: providing a burner assembly configured to combust an air/fuel mixture; providing a heat exchanger comprising a plurality of walls that form a fluid duct configured to receive a combusted air/fuel mixture from the burner assembly, and a plurality of tubes disposed across the fluid duct and configured to receive fluid therethrough; disposing the heat exchanger in a vessel that contains a fluid; allowing fluid to at least partially fill the plurality of tubes; combusting the air/fuel mixture in the burner assembly; and transferring heat resulting from the combustion of the air/fuel mixture to the fluid within the plurality of tubes.
 16. The method of claim 15, wherein the burner assembly comprises a first burner configured to combust an air/fuel mixture at a first flowrate and a second burner configured to combust an air/fuel mixture at a second flowrate.
 17. The method of claim 16, wherein the combusting the air/fuel mixture in the burner assembly comprises combusting the air/fuel mixture in each of the first burner and the second burner.
 18. The method of claim 15, wherein the allowing fluid to at least partially fill the plurality of tubes is accomplished by providing the heat exchanger with a plurality of tubes that are open to the vessel to allow ingress and egress of the fluid within the plurality of tubes.
 19. The method of claim 18, wherein the plurality of tubes comprises a plurality of vertical tubes disposed between a top wall and a bottom wall of the fluid duct and a plurality of horizontal tubes disposed between a left side wall and a right side wall of the fluid duct.
 20. The method of claim 19, wherein the plurality of vertical tubes are arranged in a plurality of sets of rows between the left side wall and the right side wall, and wherein the plurality of horizontal tubes are arranged in a plurality of sets of rows between the top wall and the bottom wall, and wherein the sets of rows of vertical tubes are alternately spaced with sets of rows of the plurality of horizontal tubes.
 21. The method of claim 15, wherein the transferring heat resulting from the combustion of the air/fuel mixture to the fluid within the plurality of tubes is accomplished by passing the combusted air/fuel mixture through the fluid duct and into contact with at least a portion of the plurality of tubes.
 22. The method of claim 15, further comprising: cooking a consumable food product within the vessel with the heated fluid. 